Abstract

Social and cultural institutions influence how societies organize themselves to extract resources, affecting the ways in which resources are used and ultimately managed. In Papua New Guinea, marine tenure rights largely determine how individuals and communities use inshore marine resources. Whether institutions of customary marine tenure can play a role in resource conservation or are simply mechanisms to avoid conflict and maximize exploitation is a matter of debate. In the Manus Province, an unusual marine tenure and trade arrangement has resulted in the community of Andra producing the majority of lime powder used for consumption with betel nut. A socioeconomic and ecological assessment revealed that more than 90% of Andra's community was engaged in lime production, an industry contributing an estimated US$102,000 ± 28,000 to the village annually. The main source of material used in lime production at Andra is live branching coral (primarily Acropora spp.). The annual removal of approximately 2,113 ± 660 m3 of coral appears to have produced significant changes in coral cover in Andra's reefs, resulting in a lower percent cover of hard corals (24 ± 2% SE) compared with neighboring reefs with little harvesting (33 ± 3% SE). Existing common-property regimes may provide incentives for individuals to sustainably use their own reef area. A lapse in supply, however, could threaten the community's virtual monopoly and provide other villages with an opportunity to gain a market share of lime production. Thus, the marine tenure and trade arrangements that facilitated Andra's position as the dominant supplier of lime to the province may result in incentives for the overexploitation of coral in ways that are paradoxical to an open-access scenario. Management interventions that aim to reduce the ecological impacts of coral harvesting should reflect the community's economic dependence on the practice and the sociocultural institutions that influence resource use.